﻿<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <h1>xxxxxxxxxxxxxxxxxxxx</h1>
    <ul>
        <li>1111</li>
        <li>22</li>
        <li>33</li>
        <li>44</li>
        <li>55</li>
        <li>66</li>
        <li>77</li>
    </ul>
    <script src="./js/jquery-3.6.0.js"></script>
    <script>
        $(function(){
            $("h1").click(function(){
                $("ul li:even").css("background","red");
            })
        })
    </script>
</body>
</html>